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Simple circuit fix?(Novice)? Answered

Built this circuit (see attachment) using 2 solar cells putting out about 5.5-6v (got crap meter atm) . 4 xAA 1.2v 2450mAh NiMH Duracell Rechargeable battery's. Found that its drawing charge from my Android phone quite rapidly.

Will another diode before usb fix the problem and block current out of device?
Or a 5v regulator in place?..... Although i read they need at least 7v to work or they will drop overall power?

or am i just talking gibberish here and need a slap?! lol!

some help would be much appreciated!

Incase of attachment  failure or watever....Link: http://neotoy.tripod.com/archive/2009/youtube/circuit-diagram.pdf

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Re-design
Re-design

8 years ago

I'm not 100% sure of what you are trying to do here, but...

Move the diode down to the usb plug so that it is between the battery connection and the usb. Your phone battery may be trying to charge the battery pack.

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scott_shot
scott_shot

Answer 8 years ago

shall i not just keep that diode (show on circuit) in place aswell to protect solar cells and add diode where you suggested?

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Re-design
Re-design

Answer 8 years ago

Add one in the battery pos. wire. That should fix your problems.

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mpilchfamily
mpilchfamily

8 years ago

The problem lies in your circuit design. You should have the solar cells tied directly to the batteries with the protection diode between the cells and batteries. Then wire the batteries to the USB plug.

If the circuit is drawing power from the phone's USB port then that is an over site of the phone manufacturer. The mini USB jack on the phone should not be allowing any power output. It should be a data connection and power input only. But it wouldn't hurt to put a diode between the batteries and the USB plug anyway. Just be aware of the voltage drop across your diodes. If you get a cheap diode that has a 1V drop then the 5V to 6V from the solar cells will only be 4V to 5V after the diode and not enough to effectively charge the batteries.

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scott_shot
scott_shot

Answer 8 years ago

Yeh interesting thought there, so i dug out several usb chargers tht fit m phone and the only difference is that some do not work, rest still give same problem.... hmmmm frustrating, well im going to add a diode between bat, and usb first and check then if no change or worse will tr a simple circuit like you suggest.

oh and the diodes im using are Salvaged from junk like 99% of components i use atm lol. Seem fairly efficient, don't notice a drop but i am using an old analog style voltage meter at the moment, SUCKS!! Digital multi-meter is bumping its way up my TO GET list Rapidly haha